


Sex Education

by MonkeyZero



Category: Tsubasa: Reservoir Chronicle
Genre: Alternate Universe - Shiritsu Horitsuba Gakuen, KuroFai Week, M/M
Language: English
Status: Completed
Published: 2017-11-29
Updated: 2017-11-29
Packaged: 2019-02-08 06:20:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,592
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12858615
Author URL: https://archiveofourown.org/users/MonkeyZero/pseuds/MonkeyZero
Summary: The only thing worse than teaching sex ed, is teaching sex ed with Fai.Yuuko is set to make Kurogane's life a living hell.





	Sex Education

**Author's Note:**

> -I wrote this for Kurofai week, with the prompt NSFW  
> -I'm not really happy with this, but I thought I'd upload it anyways  
> -my other stuff is better, I promise  
> -I tried

Kurogane came into his office to see Yuuko sitting on his desk and Fai sitting in his desk chair. Perfect. His boss and his fuck buddy. 

“Kurogane-san,” Yuuko crooned. “I need your lesson plan for May.”

“I don’t do lesson plans,” Kurogane said with a scowl. “You know that. You’ve never asked me for one before.”

“That’s all well and good for gym,” Yuuko said. “But you have to have a plan to teach the kids Sex Ed.”

“SEX ED!” Kurogane shouted. “I didn’t sign up for this.”

“It’s in your contract,” Yuuko said, waving about a piece of paper. “You signed it.”

“Nobody reads that shit,” Kurogane shouted, staring at the papers. “I’m not doing it.”

“You are if you want a job next year,” Yuuko said with a grin. “And if we have twenty pregnancies this year I will blame you.”

“What are you even doing here?” Kurogane demanded, spinning to Fai. It was a dumb question. Fai was constantly in and out of his office to annoy him and sometimes make out with him, which Kurogane always reminded him was  _ completely  _ inappropriate for work. 

“I just want to see how you’re going to do this,” Fai said with a grin. 

“Shouldn’t you be the one to teach this shit?” Kurogane demanded. “It’s science.”

“I don’t know, Kuro-tan,” Fai said with a grin. “Sex is very physical. And besides, I teach chemistry, not biology.”

“But you are qualified to teach biology,” Yuuko said thoughtfully. “We could use a science perspective.” Fai paled and Kurogane grinned at him while Yuuko lifted a finger. “I’ve decided,” she said. “The two of you will teach it together. After all, we want the children to be fully prepared for what’s ahead.”

Kurogane glared from Yuuko to Fai and back to Yuuko. “Can’t I just teach it on my own?” he asked. His relationship with sex and Fai wasn’t exactly easy right now, and the last thing he needed was  _ this.  _

“I’m hurt Kuro-tan,” Fai whined. “We’ll have so much fun!”

 

Kurogane was about to go home when Fai popped into his office. “What do you want?” He demanded.

“I thought we could work on our lesson plan,” Fai chirped. “Those kiddos need to know how to roll on condoms or you’re going to have a lot of girls sitting your of gym class.”

“Fine,” Kurogane growled. “But I’m gonna need coffee.” Dealing with Fai  _ and  _ sex ed was going to test his patience. 

To his surprise, Fai went to the coffee pot, and dropped a stack of papers on Kurogane’s desk, then left a kiss on Kurogane’s cheek. “I printed out some diagrams,” he said. “I figure we need to go over anatomy, STDs, consent, gender and sexuality, as well as puberty, mostly for the younger classes. The older ones are pretty much over that, but some of them are still popping boners in the middle of class.”

“ _ Tch _ ,” Kurogane growled, but he had to admit it was true, and it made gym class very awkward. “We should teach them about tampons too,” he added. He didn’t want to repeat the horrifying experience of trying to tell Himawari she should really go to the bathroom and clean up.

“That too!” Fai said. “And we ought to make sure everyone knows where the clitoris is. Some people are woefully uneducated you know.”

Kurogane blushed. Fai didn’t understand that these things weren’t usually talked about so openly here, but with Yuuko as the school director, he could get away with just about anything. “You’ve slept with women too?” Kurogane asked, not really knowing why he asked. Well, he knew exactly why he asked. His thing with Fai wasn’t exactly exclusive, and he wanted to know exactly how much competition he had.

“You don’t need to be a woman to have a vagina,” Fai said, pinching Kurogane’s ear. “The kids ought to know that too.”

“Yeah, I suppose you’re right,” Kurogane said. 

“How about you, Kuro-tan?” Fai said.

“I--you’ve seen me naked,” Kurogane spluttered. 

“I wasn’t asking about  _ that,”  _ Fai laughed. “I’m quite familiar with your equipment. I was asking whether you’ve been with women as well.”

“No,” Kurogane said shortly. He sighed because if he was going to ask for more from Fai he really ought to give a little. “I don’t… like many people that way. I thought I just wasn’t built for those kinds of feelings, and then there was this boy in college. But he got married and that was that, and I never really had those kinds of feelings for anybody else until…”

Fai was very quiet as he stared intently at Kurogane. “Until me?” he asked.

“Yeah,” Kurogane said. “Until you.”

Fai didn’t say anything, and Kurogane didn’t want to push his luck, so he took a sip of coffee and promptly spit it out. “Ugh,” he said. “This tastes like ass.”

“And you know what ass tastes like?” Fai said with a laugh.

Kurogane gave the smallest of smiles and shrugged.

“You dog!” Fai said and hit Kurogane on the arm.

“Don’t tell me you’ve never done it,” Kurogane said.

“I haven’t had as much sex as people assume,” Fai said with a laugh.

“I know,” Kurogane said. It had taken Fai six months to so much as kiss him, and there had always been a sense of tension--a reticence to let go. Trust didn’t come easily to Fai.

“Yuui on the other hand…” Fai said with a giggle.

“Oh really?” Kurogane asked.

“Why do you think we get the apartment to ourselves so much?” Fai asked. 

“I thought he was just being polite,” Kurogane murmured. 

“Nope,” Fai said with a laugh. He paused and smiled at Kurogane. “You know Kuro-tan, I don’t get these sorts of feelings easily either.”

“What sorts of feelings?” Kurogane asked.

“Don’t be difficult,” Fai groaned. “You now which feelings.”

“No,” Kurogane said. “I don’t know which feelings. Are you only interested in me sexually?”

“Kuro-pon,” Fai said with a sigh. He walked around the desk and settled himself on Kurogane’s lap. “I am  _ very  _ interested in you sexually, as you know.” He took Kurogane’s hand and kissed his palm. Kurogane smiled and tucked Fai’s hair behind his ear. “But I wouldn’t let you touch me like  _ that  _ if it was just about sex,” Fai said, leaning into Kurogane’s hand. 

“You deserve to be touched like this,” Kurogane said, tangling his fingers through Fai’s hair, then running his fingers down Fai’s neck. Fai purred. Kurogane grinned and added. “But you also deserve to have your ass eaten out at least once.”

Fai’s eyes flew open and he stared at Kurogane, but Kurogane could see his interest through his pants. “It  _ would _ be educational,” Fai said with a grin.

“I’ve always been better at teaching through demonstration,” Kurogane said, bringing his hands down to cup Fai’s bottom. Fai gave a nod so Kurogane squeezed his ass lightly and said, “bend over the desk, pants down.” He glanced over to see the blinds were already down. Fai must have been planning something when he came over. Kurogane walked over to lock the door and then returned to where Fai was bent over his desk. It wasn’t the first time he’d gotten Fai in this position but he still had to pause to admire the sight. 

“Are you going to start the lesson Kuro-sensei?” Fai asked. Kurogane picked up the ruler on his desk and smacked Fai lightly across his bottom.

“That’s for talking out of turn Flourite,” Kurogane growled.

“Yes Sensei,” Fai said with a giggle. 

Kurogane lowered himself onto his knees and spread Fai’s cheeks before bringing his mouth to Fai’s hole. When his tongue met Fai’s skin he felt Fai shiver and he let out a moan. Kurogane pulled away and gave Fai a light spank. “Students should listen to their lectures quietly,” he reprimanded.

“Yes sensei,” Fai said, but wiggled his hips so his ass was right in Kurogane’s face. Kurogane took the invitation and returned to licking Fai’s rim. Fai did his best to stay quiet, but the sensation was new for him. When Kurogane pushed his tongue past the ring of muscles Fai gasped. Kurogane gave him a light slap, but didn’t stop what he was doing. He gripped harder onto Fai’s buttocks as he plunged his tongue deeper, then brought his tongue out to circle around Fai’s rim and down his perineum. Fai was letting out quiet panting breaths, but was staying quiet. When Fai’s thighs began to tremble Kurogane reached forward to grip onto his cock and stroke him. He reached blindly for the hand lotion on the desk, knocking over the cup of pencils as he did so. When he too Fai in hand again, this time with more lubrication, Fai whined.

“Sensei, it’s cold,” he complained.

If Kurogane’s face hadn’t been pressed into Fai’s ass, he would have rolled his eyes. He knew Fai had only said that to get a punishment, so he brought his other hand up to strike Fai’s bottom. Fai would have marks later.

That was just enough to push Fai over the edge, and with a few more broad licks from Kurogane’s tongue, he came into Kurogane’s hand, then collapsed boneless on the desk.

Kurogane wiped his hand on a tissue, then pulled Fai’s pants up for him. “Any questions, Fourite?” he asked.

Fai pushed himself onto his hands and turned around. He grinned and said, “When will I be tested on my knowledge? I’d love to show you my proficiency.”


End file.
